1,105 research outputs found

    Time-dependent Mechanics and Lagrangian submanifolds of Dirac manifolds

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    A description of time-dependent Mechanics in terms of Lagrangian submanifolds of Dirac manifolds (in particular, presymplectic and Poisson manifolds) is presented. Two new Tulczyjew triples are discussed. The first one is adapted to the restricted Hamiltonian formalism and the second one is adapted to the extended Hamiltonian formalism

    Deshidratación de banano y cambio químicos ocurridos durante el proceso

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    Como el banano es una fruta muy alterable, es necesario transformarlaa estados más estables para prolongar su conservación.Uno de los procesos más sencillos y fáciles de realizar es la deshidratación; en nuestro país ya se efectúa pero necesita una tecnificación y un estudio químico a fondo sobre los cambios ocurridosa los diferentes constituyentes de la pulpa de banano.En este trabajo se buscaron las condiciones óptimas en lascuales podría realizarse la deshidratación del banano, para que lapérdida de nutrientes fuera mínima, y se evaluaron los cambiosquímicos ocurridos durante dicho proceso

    Dietary Fat Patterns and Outcomes in Acute Pancreatitis in Spain

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    Background/Objective: Evidence from basic and clinical studies suggests that unsaturated fatty acids (UFAs) might be relevant mediators of the development of complications in acute pancreatitis (AP). Objective: The aim of this study was to analyze outcomes in patients with AP from regions in Spain with different patterns of dietary fat intake. Materials and Methods: A retrospective analysis was performed with data from 1,655 patients with AP from a Spanish prospective cohort study and regional nutritional data from a Spanish cross-sectional study. Nutritional data considered in the study concern the total lipid consumption, detailing total saturated fatty acids, UFAs and monounsaturated fatty acids (MUFAs) consumption derived from regional data and not from the patient prospective cohort. Two multivariable analysis models were used: (1) a model with the Charlson comorbidity index, sex, alcoholic etiology, and recurrent AP; (2) a model that included these variables plus obesity. Results: In multivariable analysis, patients from regions with high UFA intake had a significantly increased frequency of local complications, persistent organ failure (POF), mortality, and moderate-to-severe disease in the model without obesity and a higher frequency of POF in the model with obesity. Patients from regions with high MUFA intake had significantly more local complications and moderate-to-severe disease; this significance remained for moderate-to-severe disease when obesity was added to the model. Conclusions: Differences in dietary fat patterns could be associated with different outcomes in AP, and dietary fat patterns may be a pre-morbid factor that determines the severity of AP. UFAs, and particulary MUFAs, may influence the pathogenesis of the severity of AP

    Social Enterprise in Spain: A Diversity of Roots and a Proposal of Models

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    The term “social enterprise” was first used, at the end of the 1980s, by organisations that promoted the social and labour integration of persons at risk of social and labour exclusion and other similar social activities. The social economy sector has since slowly introduced this term to describe its entities in order to gain recognition by society, and it is working to promote a generally accepted definition of social enterprise’s behaviour based on the principles and values of the social economy (participation, general interest...). According to Article 5 of Spanish Law 5/2011 on the Social Economy, work integration social enterprises and so-called “special employment centres” are part of the social economy, and so are all firms and entities carrying out activities following the values and principles of the social economy sector. In this context, organisations of the social economy sector also are beginning to use the “social enterprise” concept. In Spain, a debate still exists regarding its exact definition. A mix of perspectives on this concept, with different nuances, can be observed. Besides, the current context of reduced governmental budgets and social services in Spain causes social organisations to adopt new approaches to this term of social enterprise, as this type of organisation is more likely to receive funds from the European Union. This paper’s objective is to analyse all perspectives on the concept of social enterprise as well as the various social enterprise models existing in Spain. The document structure is organized as follow. In the first section, we present the context and the main concepts related to social enterprises in this country. In the second section, we provide an analysis of changes in the evolution of social enterprise criteria to identify established models and emerging patterns. In the third section, we put forward another typology, based on institutionalisation stages. Finally, we conclude by recommending an approach to future work and provide a basic bibliography on the subject

    CROMOSOMAS, LESIÓN DEL ADN Y MALFORMACIÓN NUCLEAR EN LA TORTUGA DULCEACUÍCOLA KINOSTERNON LEUCOSTOMUM (TESTUDINES: KINOSTERNIDAE)

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    Kinosternon leucostomum is one of the common freshwater turtles in Tabasco State, Mexico. However, studies of this species are limited for this region. The pollution in aquatic ecosystems from Tabasco is increasing and the effects on wildlife have not been properly made. Therefore, a chromosomic study and DNA lesion and nuclear malformation was performed in K. leucostomum from Tabasco. The karyotype in the turtle K. leucostomum is 34 msm/A + 22 T/C(2n=56 chromosomes). Also, intracellular malformations were identified: Chromosomes and DNA damage (micronucleus), binucleated cells, trinucleated cells, tetranucleated cells, cells in apoptosis and nucleoplasmic bridge, in irregular proportions. The probable origin of cell disorders is due to the presence of contaminants in aquatic ecosystems from Tabasco.La especie Kinosternon leucostomum, es una de las tortugas dulceacuícolas comunes del estado de Tabasco, México. Sin embargo, los estudios en esta especie son escasos para esta región. La contaminación en los ecosistemas acuáticos de Tabasco están aumentando cada vez más, y los efectos a la fauna silvestre no se han realizado adecuadamente. Por ello, se realizó un estudio cromosómico, de lesión de ADN y malformación nuclear en la especie K. leucostomum de Tabasco. El cariotipo en la tortuga K. leucostomum fue 34 msm/A + 22 T/C (2n=56 cromosomas). También, se identificaron malformaciones intracelulares: lesión del ADN y cromosomas (micronúcleos), células binucleadas, células trinucleadas, células tetranucleadas, células en apoptosis y puentes nucleoplásmicos, en proporciones irregulares. El origen probable de las alteraciones celulares es debido a la presencia de contaminantes en los ecosistemas acuáticos de Tabasco

    Experimental quantum tomography of photonic qudits via mutually unbiased basis

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    We present the experimental quantum tomography of 7- and 8-dimensional quantum systems based on projective measurements in the mutually unbiased basis (MUB-QT). One of the advantages of MUB-QT is that it requires projections from a minimal number of bases to be performed. In our scheme, the higher dimensional quantum systems are encoded using the propagation modes of single photons, and we take advantage of the capabilities of amplitude- and phase-modulation of programmable spatial light modulators to implement the MUB-QT.Comment: Published versio

    Flexural Behavior of Functionally Graded-Graphene Reinforced Composite Plates

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    A first order shear deformation theory based finite element numerical investigation on flexure behaviour of functionally graded thin, moderately thick and thick composite plates reinforced with graphene platelets (GPLs) is presented in this paper. The maximum deflection plays a major role in the design of composite structures. Therefore, maximum deflection and percentage maximum deflection ratio of reinforced to unreinforced composite plate are investigated for a range of GPL distribution patterns along plan and thickness directions of the composite plate. Modified Halpin-Tsai equation is used to determine the effective Young’s modulus for each layer in thickness direction for different distribution patterns. The rule of mixture is used to calculate effective mass density and Poisson’s ratio for each layer. Initially, the results from this study are verified by comparing with the reported results from the literature. Thereafter, validated methodology is used to conduct case study for a simply supported plate, focusing on the effect of thickness, GPL distribution patterns along plan and thickness directions, percentage weight fraction of GPL on the maximum deflection and percentage maximum deflection ratio of reinforced to unreinforced composite plate. It is found that by adding just 1% weight fraction of GPL, the maximum deflection can be reduced by almost 65% to 90% for all thicknesses and distribution patterns considered

    Dark energy and dark matter from an inhomogeneous dilaton

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    A cosmological scenario is proposed where the dark matter (DM) and dark energy (DE) of the universe are two simultaneous manifestations of an inhomogenous dilaton. The equation of state of the field is scale-dependent and pressureless at galactic and larger scales and it has negative pressure as a DE at very large scales. The dilaton drives an inflationary phase followed by a kinetic energy-dominated one, as in the "quintessential inflation" model introduced by Peebles & Vilenkin, and soon after the end of inflation particle production seeds the first inhomogeneities that lead to galaxy formation. The dilaton is trapped near the minimum of the potential where it oscillates like a massive field, and the excess of kinetic energy is dissipated via the mechanism of "gravitational cooling" first introduced by Seidel & Suen. The inhomogeneities therefore behave like solitonic oscillations around the minimum of the potential, known as "oscillatons", that we propose account for most DM in galaxies. Those regions where the dilaton does not transform enough kinetic energy into reheating or carry an excess of it from regions that have cooled, evolve to the tail of the potential as DE, driving the acceleration of the universe.Comment: 9 pages, 8 figures, uses revtex, submitted PR
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